An object recognition device has been developed to detect various three-dimensional objects, including a human face. In an object recognition device that detects a human face, it is desired to prevent a picture (i.e., two-dimensional image), a curved picture, or the like from being detected as a real human face. A processing algorithm may be employed to prevent such an issue, which operates to determine whether an image is of a two-dimensional picture or a three-dimensional object, and determine that a real face is captured when the image is determined to be of a three-dimensional object.
In such a processing algorithm, it is desired to further distinguish a curved picture of a three-dimensional object from the object.